Pageable + @Query + JOIN (fetch?) in Spring Data don't work

Question

I'm trying to integrate sorting with Pageable on joined fields with the use of @Query annotation from Spring Data.

1st interface's method (without @Query but with the Pageable) works like a charm. Same like when I'm fetching only one Employee with the @Query but instead of Pageable I'm using Optional<Employee> there (3rd method). But the fun begins when I try to put these two all together in one - it won't work anymore.

When I try to sort the data by name field it screams with this error:

Caused by: org.hibernate.QueryException: could not resolve property: name of: (....).model.employee.Employee

So the question is: how to tell spring to look for name in joined fields? How to do this with Spring Data?

I've already tried several things but they didn't work or I still don't know how to use them properly:

• someone suggested to add countQuery to the @Query parameters so this corresponds somehow with the pagination (spring data jpa @query and pageable)
• I've followed Baeldung's tutorial but this doesn't cover joins
• Spring-Data FETCH JOIN with Paging is not working also suggested using countQuery but I'd prefer to stick to Page<Employee> rather than List<Employee>.

I'll leave some samples of the code below. Feel free to ask for update if I omitted something important.

// Employee
@Entity
@Table(name = "employee", schema = "emp")
@Data
@NoArgsConstructor
public class Employee {
    private static final String SEQUENCE = "EMPLOYEE_SEQUENCE";

    @Id
    @SequenceGenerator(sequenceName = SEQUENCE, name = SEQUENCE, allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = SEQUENCE)
    private Long id;

    @Column(name = "employee_number")
    private String employeeNumber;

    @Column
    @Enumerated(EnumType.STRING)
    private EmployeeStatus status;

    @OneToOne(fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @Audited(targetAuditMode = RelationTargetAuditMode.NOT_AUDITED)
    @JoinColumn(name = "id_details")
    private Details details;

    // some other fields ...
}

// Details
@Entity
@Table(name = "details", schema = "emp")
@Data
@NoArgsConstructor
public class Details {
    private static final String SEQUENCE = "DETAILS_SEQUENCE";

    @Id
    @SequenceGenerator(sequenceName = SEQUENCE, name = SEQUENCE, allocationSize = 1)
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = SEQUENCE)
    private Long id;

    private String name;

    private String surname;

    // some other fields ...
}

// EmployeeDTO
@NoArgsConstructor
@AllArgsConstructor
@Data
@Builder(toBuilder = true)
public class EmployeeDTO {
    private Long id;
    private String employeeNumber;
    private String status;
    private String name;
    private String surname;

    // some other fields ...
}

// EmployeeRepository
@Repository
public interface EmployeeRepository extends JpaRepository<Employee, Long> {

    // 1st method
    Page<Employee> findByStatus(EmployeeStatus status, Pageable pageable);

    // 2nd method
    @Query(value = "select e from Employee e join e.details where e.status = :status",
            countQuery = "select count(*) from Employee e join e.details where e.status = :status")
    Page<Employee> getEmployeeDetails(@Param("status") EmployeeStatus status, Pageable pageable);

    // 3rd method
    @Query("select e from Employee e join fetch e.details where e.id = :id")
    Optional<Employee> findByIdWithDetails(Long id);

    // ...
}

// EmployeeService
@Service
public class EmployeeService {

    private final EmployeeRepository employeeRepository;
    private final EntityDtoConverter entityDtoConverter;

    @Autowired
    public EmployeeService(EmployeeRepository employeeRepository, EntityDtoConverter entityDtoConverter) {
        this.employeeRepository = employeeRepository;
        this.entityDtoConverter = entityDtoConverter;
    }

    public EmployeeResponse getEmployeesByStatus(EmployeeStatus status, int pageSize, int pageIndex, Sort.Direction sortDirection, String sortColumn) {
        Page<EmployeeDTO> employeePage = employeeRepository.findByStatus(status, PageRequest.of(pageIndex, pageSize, Sort.by(sortDirection, sortColumn)))
                .map(entityDtoConverter::convertEmployeeBaseToDto);
        return new EmployeeResponse(employeePage);
    }

    public EmployeeResponse getEmployeeDetails(EmployeeStatus status, int pageSize, int pageIndex, Sort.Direction sortDirection, String sortColumn) {
        Page<EmployeeDTO> employeePage = employeeRepository.getEmployeeDetails(status, PageRequest.of(pageIndex, pageSize, Sort.by(sortDirection, sortColumn)))
                .map(entityDtoConverter::convertToEmployeeWithDetailsDto);
        return new EmployeeResponse(employeePage);
    }

    // ...
}

// EntityDtoConverter
@Component
public class EntityDtoConverter {

    public EmployeeDTO convertEmployeeBaseToDto(Employee entity) {
        return EmployeeDTO.builder()
                .id(entity.getId())
                .employeeNumber(entity.getEmployeeNumber())
                .status(entity.getStatus())
                .build();
    }

    public EmployeeDTO convertToEmployeeWithDetailsDto(Employee entity) {
        return convertEmployeeBaseToDto(entity).toBuilder()
                .name(entity.getDetails().getName())
                .surname(entity.getDetails().getSurname())
                .build();
    }

    // ...
}

EDIT:

This is one of the methods of my rest controller:

@GetMapping
public ResponseEntity<EmployeeResponse> getEmployeesByStatus(EmployeeStatus status, int pageSize, int pageIndex, String sortDirection, String sortColumn) {
    try {
        EmployeeResponse employeeResponse = employeeService.getEmployeesByStatus(status, pageSize, pageIndex, Sort.Direction.fromString(sortDirection), sortColumn);
        return employeeResponse.getTotalElements().equals(0L) ? ResponseEntity.noContent().build() : ResponseEntity.ok(employeeResponse);
    } catch (Exception e) {
        log.error(ERROR_MESSAGE, e);
        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).build();
    }
}

Answer 1

Try below code.

Specification<Employee> joins = (employee, query, cb) ->  {
            Join<Employee, Detail> details = employee.join("details");

            return cb.and(
                    employee.equal(employee.get("name", name)),
                    details.equal(details.get("name", detailName))
            );
        };

        PageRequest pageRequest = new PageRequest(0, 2, new Sort(Sort.Direction.DESC, "name"));

        Page<Employee> customerPage = employeeRepository.findAll(joins, pageRequest);

Here we are trying to inform JPA that this name is foreign key for Employee table.